As the apparatus configured to continuously manufacture granulated or coated particles, there have been known manufacturing apparatus adopting a so-called spray granulation system in which a raw material solution obtained by dispersing or dissolving raw material powder is sprayed from a spray nozzle and dried in a processing container (Patent Literatures 1 to 4 described below).
In an apparatus disclosed in Patent Literature 1, an ejector is arranged below a nozzle configured to spray a raw material solution. The ejector includes an introducing tube, and a blowing tube from which hot air is blown into the introducing tube. Fine particles or small-diameter granules in a fluidization chamber are guided by the ejector to the vicinity of the nozzle, and are coated with spray liquid droplets sprayed from the nozzle. Further, the ejector increases kinetic energy of the fine particles or the small-diameter granules at the vicinity of the nozzle, thereby preventing adhesion of the particles. The particles subjected to coating process in the fluidization chamber are fed through a discharge port to a classification mechanism, whereas the fine particles or the small-diameter granules that do not attain to predetermined particle diameter and weight are blown up by air supplied into the classification mechanism, and are returned to the fluidization chamber.
In an apparatus disclosed in Patent Literature 2, near an upper end of a conical portion of a spray drying section, there is provided a part configured to introduce an air stream downward or obliquely downward along an inner surface of the conical portion. Dried powder, which adheres to the inner surface of the conical portion after completion of a drying step, is blown off by the air stream introduced from the air stream introducing part. In this manner, the dried powder is forcibly transferred to a fluidizing and granulating section provided below the spray drying section, and is prevented from adhering to and accumulating on the inner surface of the conical portion. A cyclone is arranged in a halfway portion of an exhaust gas line, and fine powder mixed in an exhaust gas is collected by the cyclone to be returned to the fluidized bed granulating section.
In an apparatus disclosed in Patent Literature 3, there are provided a plurality of jet nozzles configured to blow a high-pressure gas toward a fluidized bed of powder in a granulation chamber. With this configuration, aggregation of particles is prevented.
In an apparatus disclosed in Patent Literature 4, there are provided a plurality of nozzles configured to jet a fluid toward an inner wall surface of a granulation chamber. The fluid to be jetted from the nozzles can be switched among a gas, a liquid, and steam.